Good for you for separating them! I wish more ham-pair owners were like you. And good for having a Sapir cage too! That's one mistake I made with my pair. I had a spare cage, but it didn't have a lid, and apparently it was short enough for Tangerine to take a leap of faith out of it (to my horror). Well anyways let me get back to what I was saying
Unfortunately, re-bonding isn't really an option once they've fallen out. Keeping them together wouldn't have had any benefits for the hamsters, and possibly you as well. It would be stressful for the hamsters and stress would result in a weakened immune system for both of them. Whenever my hamsters began falling out, I had trouble falling asleep every night. I was terrified that I would wake up to find a dead or very injured hamster(s). Once they were separated my stress was relieved immensely. I wouldn't wish that kind of stress upon anyone.
The hamsters might act a little more skittish than usual in the next week. After all, it's probably the first time they haven't lived with another hamster! But they'll settle in soon.
Good luck p, and if you have more questions please don't hesitate to ask